When regional renewable generation systems are interconnected, the variations in their power outputs tend to cancel out and the total fluctuation is reduced. By interconnecting wind and solar farms with proper sizes located in areas with different weather conditions, the reduction of these fluctuations and the need for a backup is possible. However, to achieve this, there is a need to define which type of renewable energy to install and how much capacity is needed in each region. So, in this paper, the type and capacity of the renewable energy systems are identified in each region, by developing a genetic algorithm-based optimization program.

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The objective of this study is to evaluate the performance of SOFC (Solid oxide fuel cell) installed in office buildings. The higher efficiency of power generation is considered advantageous for electricity oriented users like offices in commercial sector. Optimization model to minimize the system cost with co-generation was employed to analyze how SOFC could be competitive compared with conventional gas engine technology. The results suggest that SOFC is required to have the cost at most 1.3 times as large as gas engine co-generation even though SOFC is effective to reduce the primary energy consumption.

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The authors have examined heat transportation based on ammonia absorption cycle named STA. STA recovers discharged heat and converts it into cooling. New type of STA was proposed in this study, which incorporates two evaporators to provide cooling at different temperature simultaneously. The objectives of this study are to investigate the static performance such as cooling output and COP as well as to observe the interaction between two refrigeration cycles of the proposed STA by non- steady state simulation. The static cycle simulation reveals that cooling output of each evaporator is proportional to refrigerant mass flow. The result of dynamic simulation shows that the change of cooling load in one side affects the temperature behavior of the other side to some extent. Because the effect seems small, it implies that the two evaporators can be controlled separately as the conventional way.

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The output characteristics affected by stack shape in loop-tube type thermoacoustic engine are experimentally investigated. The loop-tube type thermoacoustic engine consists of a stack, heat exchangers, resonance tube, and working gas. For the thermoacoustic engine, a thin tube ceramic honeycomb was introduced as a stack, and air was introduced as a working gas. The system performance is experimentally examined for various cell densities and lengths of stack, and heater input to one side of stack. Here, the work intensity, that is the power intensity of the generated sound, is theoretically estimated using a two-sensor method from the pressure amplitude and phase difference of the sound inside a resonance tube. The output characteristics of the sound generator are shown by the work intensity and the conversion efficiency from heater input to sound intensity.

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Fossil fuel depletion and global warming have become global social issues. As part of the solution, in this study, we focus on the physical properties of a gas hydrate for the development of a clean generation system. Because the necessary heat can be covered by a low temperature heat source this system can contribute to reducing negative environmental impact and saving energy. In this paper, we model a gas hydrate power generation system and report the response characteristics based on the relationship between the electrical components of the load and the power quality.

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In a cold region, because, the energy demand for residential heating is high in winter season, energy saving, greenhouse gas emission, and air pollution are major issue. On the other hand, in recent years, gas hydrates have emerged as new energy sources. In this work, a distributed energy system is proposed by exploiting the unique state-change property of CO_2 hydrate through the heat cycle which employs the ambient cold air and the geothermal heat, as cold and hot medium, respectively. The proposed system is environmentally friendly because it does not burn any type of fossil fuel and also input heat energy are supplied by a renewable source. In this study, we clarified the characteristics of the output of the proposed generation system by examinations of a test equipment.

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Isobaric heat capacity of liquid R245fa was measured. Our group constructed a flow-calorimeter in 1985 for measuring specific isobaric heat capacity of HFC liquid refrigerants. In 2014, the authors modified the apparatus of a flow calorimetry with an improvement for achieving a stable mass-flow-rate by introducing plastic accumulators and two parallel needle valves. We confirmed that the apparatus is able to measure isobaric heat capacity with unmeasurable level heat loss and repeatability within the uncertainty. The measurements were obtained at fifteen points of state parameters along pressures of 500 kPa and 800 kPa in a temperature range from 278 K to 343 K. The expanded uncertainty (coverage factor of k=2) for the heat capacity values is predicted to be between 0.36 and 1.12 %. The purity of the sample liquid R245fa is analyzed as being better than 99.99 % in mass fraction by the manufacture.

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Ice adhesion often causes the accident accompanied by an economic loss. So, it is important to know real ice adhesion force. Ice adhesion force is often measured by the method that a shearing force is given at the interface between the ice and solid surface. However, the measured value is an apparent ice adhesion force including a force breaking ice. If ice diameter approaches the nano-scale, relative evenness of the solid surface for the ice increases. At that time ice adhesion force without a force breaking ice can be measured. So, in this paper, the adhesion forces of ices with diameters less than 100 nm to the metal test plates are measured by the SPM, the measured values are compared with those measured in the macro-scale.

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Authors examined active control of supercooling degree by using adsorption of surfactant molecules to an interface, and it was clarified that it was possible to actively control supercooling degree by variation of surfactant concentrations. In this paper, when other surfactant molecules with smaller sizes are added to let them be adsorbed to the interface without adsorption of original surfactant molecules at a critical micelle concentration where adsorbed area of original surfactant molecules to the interface becomes a maximum, effect of the addition of smaller surfactant molecules on the supercooling degree is investigated.

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This paper describes about "Ultra Lightweight Vehicle" (ULV) which is able to drive with smallest size of body and the least energy. Small size and environmental-friendly mobility is demanded from recent automobiles social conditions such as the drying up the fossil fuel, air pollution, and the traffic jam. Then we examined equipping the air engine as a part of the development of ULV. As a result of driving test of the go-cart which carried the air engine, the maximum speed was 24.1km/h, and the distance covered per one filling was 821m. We carried out the noise level was about 90dB. In addition, we designed the performance test device of the air engine, and produced it. As a result of the test, the max power was about 450 W, and adiabatic efficiency was about 44%. According to the above results, we designed and developed ULV-Air with the air engine.

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The Ionic Semiconductor has been a polymeric semiconductor that contained with some rare earth metal oxides. This semiconductor was an equipment of environment conformity type, since the environmental loading such as power consumption was remarkably small, and it was man and beast harmless. Various solvents and/or atmosphere were given powerful reduction effect (antioxidative effect) by the convenient and safety method with the semiconductor. In the solvent and/or atmosphere the new active species were generated with the action of this semiconductor. These active species were applied in following fields; (1) the battery active reinforcement agents toward various secondary batteries, (2) the power storage system based on the regeneration secondary battery, (3) the energy-saving type heat exchanging systems applied circulation efficiency improvement with viscosity lowering phenomenon of heat exchange medium, (4) the additive for fuel oil and/or engine oil with fuel consumption reduction effect and exhaust gas clear effect, (5) the cooking oil degradation prevention system toward deep fling manufacturing process, (6) refrigeration and/or thawing system toward keep of freshness of the food and/or selective accelerated ripening, and so on. These effective phenomena were manifested by the active species estimated with being analogue of solvated electron. The authors report the outline of practical application examples of environmental conformity type our products and/or our systems.

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This study aims to improve the heat exchange performances of heat radiator fins by generating ionic wind on the fin surfaces. The ionic wind generator investigated in this study consisted of a glass plate, a discharge electrode, a bias electrode, and a ground electrode on the back of the glass plate. Dielectric barrier discharge (DBD) was generated by applying AC high voltage of around 14 kHz between the discharge electrode and the ground electrode. Flow velocities were known by measuring dynamic pressure with a glass capillary tube. Test results showed that flow velocity reached a maximum at 4 mm downstream from the edge of the discharge electrode, whereas DC electric field existed until 5 mm downstream of the edge. It suggested the influence of staying air on the bias electrode.

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Toward reducing the air-conditioning power consumption of the data center, using the low-temperature outside air is effective. The pump cycle is one of the methods of low-temperature outside air utilizatioa The pump cycle is a heat transport technique that uses a refrigerant pump that consumes a small amount of energy compared to a compressor. In this paper, we analyzed the dynamic characteristics of the Pump cycle to the amount of circulating refrigerant change by simulation

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A coupled dynamic analysis method for an air-conditioning system and an air-conditioned room is constructed to develop an operational management approach for multi-split type air-conditioning systems for buildings. This method weakly couples an unsteady computational thermo-fluid analysis of the air-conditioned room with a dynamic cycle simulation of the air-conditioning system, which are separately coded, through the file input-output operation of the air condition in the indoor unit by an upper-level control program. The dynamic behavior of the air-conditioning system is obtained by the numerical solution under the inlet air condition of the indoor unit outputted from the unsteady computational thermo-fluid analysis. The time variations in the temperature distribution inside the air-conditioned room are derived by the numerical solution under the outlet air condition of the indoor unit outputted from the dynamic cycle simulatioa A case study for an electric air-conditioning system and an air-conditioned laboratory reveals a coupled behavior of the analysis object

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Storage-type water heating systems have been used widely in residential applications, and it is important to make the sizes of storage tanks smaller for space saving. One of the ways to realize that is to incorporate phase change materials (PCMs) into the tanks and increase the density of stored heat by utilizing the latent heat of PCMs. A simulation model has been proposed to analyze the performance of a water heating system with a storage tank using PCM. In this paper, the validity of the simulation model is investigated by comparing experimental and simulated results concerning temperature distributions and changes of the storage tank and PCM during changing, storage, and discharging. The investigation shows that the simulated results coincide with experimental ones qualitatively.

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